The present invention generally relates to a folding ramp carried on the end of a platform railcar for loading and unloading trailers. More particularly, the invention relates to an automatically engaged, manually released safety latch to secure the folding ramp in a raised and stored position for train operation.
Railroad cars are often used to transport highway trailers. One method of loading highway trailers or other wheeled vehicles onto railroad cars having decks for carrying vehicles is by what is called circus loading. A ramp is placed at one end of a string of rail car units, and then each vehicle is loaded in sequence by driving them up the ramp and along the decks of the railroad car units. Bridge plates typically span the gaps between successive rail car units. Although circus loading is common for a string of cars, such end-loading can be used for individual rail car units, or multiple rail car units as may be convenient.
It is common for portable ramps to be employed to permit trailers to be driven up onto the rail cars. In recent years there has been an emphasis on reducing the loading time required in intermodal train service, and in increasing the length of intermodal trains. Another trend has been toward the increased use of articulated railroad cars, as opposed to single unit cars employing standard separable couplers. Articulated railroad cars are often able to carry the same number of highway trailers as coupled individual cars, but have fewer rail car trucks, thus increasing the lading per truck and reducing the effective ratio of the railcar weight to lading weight, while also reducing the slack action along the train consist in service.
When a large number of articulated cars are used, and a lengthy train is to be loaded, it is important that loading proceed in an orderly and efficient manner. The railcars are split at the separable coupler ends, ramps are moved into place, and wheeled vehicles are loaded in both directions running away from the location of the split. Once loaded, the train is re-assembled by re-joining the coupler ends, and the train departs the loading terminal.
The loading of highway trailers has certain special features. First, the highway trailers are backed into position sequentially using a hostler truck, or tractor. Backing a highway trailer on a flat car is a task requiring some care. It is advantageous to align the loading ramp well before commencing loading of the trailers. At present, time is often wasted aligning the ramps. It would be highly advantageous to have a ramp that can be aligned relatively quickly and easily.
Another method of loading highway trailers onto railcars is by use of large overhead cranes, which pick the trailers up and place them into position for transport on the railcar decks. This requires very large and expensive equipment, however, and can be done only with reinforced trailers. A large portion of existing highway trailers cannot be handled in this manner.
In one aspect, the invention generally features a latching mechanism for use with a raisable and lowerable folding ramp having a bridge section and a toe section, such ramp being carried on one end of a railway car. The latching mechanism comprises an arm-like member pivotally connected at one end thereof to a predetermined structure of such railway car and a latch means attached to and extending outwardly from one of the bridge section and toe section of such folding ramp. A latching head portion is disposed at a radially opposed end of such arm-like member, and the latching head portion including a means for securing the latch means. A rotatable latching member is disposed in the latching head portion to engage and lock such latch means when such folding ramp reaches a fully raised position.
It is therefore the primary object of the present invention to provide a safety latch to secure the folding ramp of a railcar in the raised and stored position for proper and safe train operation.
Another object of this invention is to provide a safety latch to secure the folding ramp of a railcar in the raised and stored position, which can be automatically engaged into the locked position.
It is still another object of this invention to provide a safety latch to secure the folding ramp of a railcar in the raised and stored position which can be only manually released from the locked position, and then readies itself to be automatically engaged into the locked position.
A further object of this invention is to provide a safety latch to secure the folding ramp of a railcar in the raised and stored position, which is able to automatically reset the latching mechanism into the locked position when it has been momentarily released.
In addition to the above-described objects and advantages of the ramp latching mechanism of this invention, various other objects and advantages of the present invention will become more readily apparent to the persons who are skilled in the same and related arts from the following more detailed description of the invention, particularly, when such description is taken in conjunction with the attached drawing figures and the appended claims.